Many electrical parts include insulation, such as enamel or other primary insulation, close-coupled, or sheathed, over wires. Many also include a secondary insulation, such as a varnish provided over the sheathing.
When complete, the insulation keeps electrical current from emanating from the wire undesirably. When flaws are present in both layers, such as by the primary insulation being too thin in an area adjacent an air bubble in the secondary insulation, unwanted partial discharge (PD) can result. A PD can occur, for example, in such an air bubble.
Numerous challenges exist in identifying problematic flaws effectively and efficiently. A primary challenge is that traditional techniques require significant manual involvement, for instance, such as switching manually between phases of the electrical part being tested.